Colorectal cancer (CRC) screening rates are far below recommendations by the US Preventive Services Task Force. Among the nearly 100 million adults aged 50 or older in the United States, less than 50% have ever had a screening endoscopy (Shapiro et al., 2008). A further concern is that the screening rate for minority and low socioeconomic groups is even lower (Doubeni et al., 2009;Johnson-Kozlow, et al., 2009). These disparities are not explained away by individual coverage of health insurance. Instead, there is speculation that a complex combination of socioeconomic disadvantage and place of residence may contribute to these persistent disparities in screening (Christie, et al., 2009;Doubeni et al., 2009;Henry, Niu, Boscoe, 2009). An emerging area of interest in public health in general-and cancer screening in particular-is the effect that contextual forces may play in shaping use of health care services (Arcury et al., 2005;Hiscock et al., 2008;Onega et al., 2008). A better understanding of the role of other contextual barriers to screening-such as the supply of medical resources-may not only be important for understanding the barriers to colorectal cancer screening, but may also be more amenable to policy interventions (e.g., these types of barriers fit within current health care reform efforts). The research we are proposing will provide a basis for understanding the contextual factors impacting colorectal cancer screening, as well as new insights on the role of factors that contribute to disparities in CRC screening. Data from this study can be used to develop strategies to increase colorectal cancer screening and reduce disparities. Our first aim will identify community level barriers for colorectal cancer screening including demographic characteristics, medical resource supply, and insurance market. Our second aim will determine which community level barriers contribute to race/ethnic disparities in colorectal cancer screening. To address the specific aims, analysis will be performed on secondary data from the 2005 National Health Interview Survey (NHIS) Cancer Control Module linked with the 2007 Area Resource File (ARF). NHIS is a population-based survey of individuals, and ARF is a collection of county level data. NHIS was collected under statutory authority that requires strict protection of respondent confidentiality. To maintain confidentiality, public versions of these data do not contain aggregate level identifiers. To facilitate access to contextually linked files, the National Center for Health Statistics (NCHS) has established research data centers. NCHS will link the NHIS and ARF through the Research Data Center. Access to a contextual-link file for these data sets requires application to NCHS and investigator guarantees to maintain confidentiality. PUBLIC HEALTH RELEVANCE: Colorectal cancer screening may be perceived to be unpleasant, embarrassing, frightening, and time- consuming, and this perception is a major barrier relative to other types of preventive screening and likely among the major reasons that colorectal cancer screening is far below recommended levels. Aside from improved technology that would reduce the time and unpleasantness of the procedure, public health officials are left with identifying and removing as many other barriers to screening as possible. Factors related to the structure and organization of the community not only contribute to disparities in colorectal cancer deaths, but an advantage of focusing on community level characteristics is that they might be better able to ameliorate population wide disparities in colorectal cancer compared to individual level interventions for patients and providers.